毕业设计-基于单片机的pwm信号输出系统.rar

毕业设计-基于单片机的PWM信号输出系统

包括电路图，源程序


摘要
　　　随着电力电子技术的飞速发展，PWM技术应用越来越广泛。同时PWM技术本身也发展迅速，各种新理论层出不穷。PWM技术结合了电力电子技术、计算机技术、现代控制理论，具有抗干扰性强、效率高、可靠性好等显著优点，已经在交流逆变、开关电源等领域得到广泛应用。
  本文在研究PWM技术当前发展状况基础上，设计了一种基于单片机的PWM信号输出系统。首先对系统结构和PWM软件算法进行了研究和分析，包括对各种PWM产生方法的对比分析和对称规则采样法的仔细研究以及系统的功能分区和总体结构。在总体设计完成后又设计了硬件电路各个单元模块。然后采用C语言编程实现了系统功能，完成设计目标。最后对设计的系统进行了计算机仿真。
　　　本设计是基于单片机控制的PWM信号输出系统，系统以AT89C52单片机为核心，采用SPWM软件生成法中对称规则采样法，用扩展按键中断方式输入有关控制信号及参数，可以实现频率、占空比、输出时间可调的直流斩波PWM信号和频率、调幅比、输出时间可调的SPWM信号，并在LCD1602上实时设置参数及输出状态监视。
　　　
关键词：单片机；PWM； SPWM；信号；规则采样法
　　　ABSTARCT
　　　As the developing of power electronic technology, PWM technology has applying to more and more field. At the same time, PWM technology itself has taken a great progress, lots of new theory has emerged. PWM technology takes advantages of power electronic, computer technology, and modern control theory, has strong ability of anti-interference, and is more efficiency, reliable. It has applied to vast field ,such as AC converter, DC chopper.
　　　This paper firstly, analysis the situation of PWM technology’ development, then, designed a PWM signal output system based on SCM. At the beginning, we study the soft algorithm of PWM, including comparison and analysis of several PWM   algorithm and deep analysis of regular-sampling. We also designed the system structure. Following , hardware and software is designed. Every hardware module is designed with the computer, and the software is written in C language. At last, we take a simulation.
　　　The system is based on AT89C52. It use buttons to input parameters. It can output single polar PWM signals. The signal’s frequency, duty-cycle, output time can be changed. What’s more, all information is showed in a LCD1602, so that it is easier to communicated with the system.

Index terms: SCM; PWM; SPWM; signal; regular-sampling
目    录

1 绪论 1
1.1 PWM的背景、应用及发展趋势 1
1.2 PWM原理 1
1.3 本文的主要工作 2
2 系统方案设计 3
2.1系统PWM算法 3
2.1.1等面积法 3
2.1.2硬件调制法 3
2.1.3软件生成法 3
2.2 系统结构 5
2.3涉及元器件简介 5
2.3.1 AT89C52介绍 5
2.3.2 LCD1602简介 8
2.4  仿真工具介绍 9
2.4.1 Protues简介 9
2.4.2 Keil uVision2简介 11
3硬件电路设计 13
3.1电源 13
3.2单片机复位电路 14
3.3单片机时钟电路 14
3.4按键中断 15
3.5显示电路 16
3.6输出电路 17
3.7 SPWM测试电路 17
4 软件设计 19
4.1软件总流程 19
4.2 直流斩波PWM软件计算法 19
4.3 SPWM软件计算法 20
4.4输出时间控制 22
4.5按键中断 23
4.6 LCD1602编程 26
4.7显示设计 27
5 系统调试 31
5.1系统的调试 31
5.2系统仿真过程 31
6 结论 36
参考文献 37
附录 38
翻译部分 50
外文原文： 50